feat(provider): summarize a Skill call by the skill it loads

[pvbhanuteja]

When Claude loads a skill, the transcript records a Skill tool call that names it in input.skill:

{"type":"tool_use","name":"Skill","input":{"skill":"ponytail:ponytail"}}

summarize_tool had no arm for Skill, and the default one reads description and then query, so the detail panel showed every skill load as a bare Skill. This adds one line to the lexicon so the panel shows the skill's name.

Detail panel, same transcript:

before:  ✓ Skill                                  12:49:00
after:   ✓ Skill ponytail:ponytail                12:49:00

Checked on a Claude Code 2.1.286 session. cargo fmt --check, cargo clippy --all-targets (no warnings) and cargo test all pass. The goldens don't include summaries, so they're unchanged.

Not in this PR:

• Codex: it has no structured skill-load record. It reads SKILL.md through a shell command, which already shows up as that command.
• Skills typed by the user as /skill (no Skill call), and showing skills on the cards or chips. Happy to add either if you want them.

🤖 Generated with Claude Code